Issuing Neotel airtime instead of Telkom airtime

My Mom requested to purchase Telkom airtime from the Spar in Bothasig. She brought it home for me to load and when I got it I told her that they issued Neotel airtime. Well my Mom does not even know who is Neotel, so she definitely did not request it. She then went to the Spar this morning and was told, sorry, but you should have checked when you bought it. This is unacceptable as she should have been issued with what she asked for. How can you just say sorry for something YOU did wrong and expect the customer to carry the cost of YOUR mistake and that with a pensioner too. Shame on you, I expect you to correct this immediately otherwise I will be taking this to the papers too. This is theft.